Biosynthesis of Bacterial Cellulose by Extended Cultivation with Multiple Removal of BC Pellicles.

Extended cultivation with multiple removal of BC pellicles is proposed herein as a new biosynthetic process for bacterial cellulose (BC). This method enhances the BC surface area by 5-11 times per unit volume of the growth medium, improving the economic efficiency of biosynthesis. The resultant BC gel-films were thin, transparent, and congruent. The degree of polymerization (DP) and elastic modulus (EM) depended on the number of BC pellicle removals, vessel shape, and volume. The quality of BC from removals II-III to VII was better than from removal I. The process scale-up of 1:40 by volume increased DP by 1.5 times and EM by 5 times. A fact was established that the symbiotic Medusomyces gisevii Sa-12 was adaptable to exhausted growth medium: the medium was able to biosynthesize BC for 60 days, while glucose ran low at 24 days. On extended cultivation, DP and EM were found to decline by 39-64% and 57-65%, respectively. The BC gel-films obtained upon removals I-VI were successfully trialed in experimental tension-free hernioplasty.

A differentiated approach to repeat small-bowel anastomoses in patients with postoperative peritonitis: a prospective cohort study.

BACKGROUND: Postoperative peritonitis still remains the cause of a high mortality rate in emergency abdominal surgery. Here we aimed to evaluate the efficacy of different surgical strategies for small-bowel perforations that resulted in postoperative peritonitis. METHODS: Surgical management results for 140 patients with postoperative peritonitis due to small-bowel perforations, necrosis and anastomotic leakage were comparatively analyzed. Using the APACHE-II and MPI scoring systems, different surgeon attitudes were examined in three patient groups (primary anastomosis, delayed anastomosis, and enterostomy). RESULTS: The surgical approach in patient group I (n = 47, APACHE-II 11.7 ± 1.2, MPI 14.7 ± 1.3) involved the closure of small-bowel perforations or small-bowel resection to place primary anastomosis. The mortality rate was 17%. Patient group II (n = 48, APACHE-II 16.8 ± 0.7, MPI 19.3 ± 0.3) underwent delayed small-bowel anastomosis during planned relaparotomies. The mortality rate was 18.8%. Because patients in patient group III (n = 45, APACHE-II 22.3 ± 1.3, MPI 24.6 ± 1.2) were in very critical condition, anastomoses were not placed after bowel resection, and the surgical procedure was completed with enterostomy. The highest mortality rate of 37.8% was documented in this patient group. CONCLUSION: The differentiated surgical approach undertaken herein using delayed small-bowel anastomosis in more serious patients with postoperative peritonitis was able to mitigate the risk of recurrent anastomotic leaks and was not accompanied by a considerable rise in mortality. The mortality for primary repair and delayed primary closure was basically the same (17.0% and 18.8%, p = 0.03); however, delayed anastomosis in the patients with postoperative peritonitis at higher APACHE-II and MPI scores for severity of illness showed 15.1% less complications in the form of anastomotic leaks (p = 0.04).

Early morphological changes in tissues when replacing abdominal wall defects by bacterial nanocellulose in experimental trials.

Experimental trials were done on five dogs to explore if an anterior abdominal wall defect could be repaired using wet (99.9%), compact BNC membranes produced by the Мedusomyces gisevii Sa-12 symbiotic culture. The abdominal wall defect was simulated by middle-midline laparotomy, and a BNC membrane was then fixed to open aponeurotic edges with blanket suture (Prolene 4-0, Ethicon). A comparative study was also done to reinforce the aponeurotic defect with both the BNC membrane and polypropylene mesh (PPM) (Ultrapro, Ethicon). The materials were harvested at 14 and 60 days postoperative to visually evaluate their location in the abdominal tissues and evaluate the presence of BNC and PPM adhesions to the intestinal loops, followed by histologic examination of the tissue response to these prosthetics. The BNC exhibited good fixation to the anterior abdominal wall to form on the 14th day a capsule of loose fibrin around the BNC. Active reparative processes were observed at the BNC site at 60 days post-surgery to generate new, stable connective-tissue elements (macrophages, giant cells, fibroblasts, fibrin) and neocapillaries. Negligible intraperitoneal adhesions were detected between the BNC and the intestinal loops as compared to the case of PPM. There were no suppurative complications throughout the postsurgical period. We noticed on the 60th day after the BNC placement that collagenous elements and new capillary vessels were actively formed in the abdominal wall tissues, generating a dense postoperative cicatrix whose intraperitoneal adhesions to the intestinal loops were insignificant compared to the PPM graft.